Tracing the incorporation of the "ninth sulfur" into the nitrogenase cofactor precursor with selenite and tellurite.
Nat Chem
; 13(12): 1228-1234, 2021 12.
Article
em En
| MEDLINE
| ID: mdl-34635813
ABSTRACT
Molybdenum nitrogenase catalyses the reduction of N2 to NH3 at its cofactor, an [(R-homocitrate)MoFe7S9C] cluster synthesized via the formation of a [Fe8S9C] L-cluster prior to the insertion of molybdenum and homocitrate. We have previously identified a [Fe8S8C] L*-cluster, which is homologous to the core structure of the L-cluster but lacks the 'ninth sulfur' in the belt region. However, direct evidence and mechanistic details of the L*- to L-cluster conversion upon 'ninth sulfur' insertion remain elusive. Here we trace the 'ninth sulfur' insertion using SeO32- and TeO32- as 'labelled' SO32-. Biochemical, electron paramagnetic resonance and X-ray absorption spectroscopy/extended X-ray absorption fine structure studies suggest a role of the 'ninth sulfur' in cluster transfer during cofactor biosynthesis while revealing the incorporation of Se2-- and Te2--like species into the L-cluster. Density functional theory calculations further point to a plausible mechanism involving in situ reduction of SO32- to S2-, thereby suggesting the utility of this reaction to label the catalytically important belt region for mechanistic investigations of nitrogenase.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Enxofre
/
Telúrio
/
Coenzimas
/
Ácido Selenioso
/
Proteínas Ferro-Enxofre
/
Nitrogenase
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article